This disclosure relates to a storage system, an electronic device and an electric vehicle, which utilize power from the storage system, and a power system.
Recently, application of a secondary battery such as a lithium-ion battery has been rapidly expanded to an electric power storage device in which the second battery is combined with a new energy system such as a photovoltaic cell and wind power generation, a vehicle storage battery and the like. In a case in which a great number of storage devices such as unit cells (electric cells, also referred to as cells; simply appropriately referred to as cells in a following description) are used for generating significant power, a configuration in which a plurality of storage modules is connected in series is adopted. In the storage module, a plurality of, for example, four cells are connected in parallel and/or in series to configure a battery block. A great number of battery blocks are stored in an exterior case and the storage module (also referred to as an assembled battery) is configured.
Further, a configuration to connect a plurality of storage modules to each other and provide a control device common to a plurality of storage modules (such configuration is referred to as a battery system) is known. The configuration is such that each storage module includes processing means (microprocessor MPU) and communicates between the MPU and the control device through communication means.
In the battery system, it is required to shut down (or power down) the storage system when a battery voltage becomes equal to or lower than a predetermined voltage or when an SOC (State Of Charge) of a battery unit becomes substantially 0 in order to prevent an over discharge of the battery. When a charging voltage is input, control to detect the input of the charging voltage to return from a shutdown state to a charging state is required in order to return from an off-state to the charging state. It is required to continue supplying the power to a circuit for the control even in the shutdown state. Following Patent Document 1 discloses that, when the over discharge is detected, it is put into the shutdown state and discharge is inhibited by decreasing a current flowing to the circuit in the shutdown state, so that the power may be supplied to the circuit for a long period of time.